The phenomenon of climate change is taking its toll in terms of salinity intrusion in the coastal areas of Bangladesh. As an inevitable consequence, it will gradually extend towards inland water and soil. Salinity is therefore an environmental problem which is expected to get exacerbated by climate change and sea level rise in the future. Salinity intrusion is caused mainly by a reduction of fresh water flow in rivers and higher salinity levels have deepening impacts on agriculture, aquaculture, and domestic and industrial water use.
Increased soil salinity has multifaceted impacts limiting the growth of standing crops vis-à-vis overall crop production and constraining the livelihood operation of people along the coastal belt there. Water salinity causes an increase in soil salinity which further decreases the agricultural productivity and creates enormous pressure on food security.
According to a research work by an international organisation 'Practical Action', agricultural land in five upazilas of Khulna and Satkhira districts, decreased by 78,000 acres between 1995 and 2015. At the same time, the area of shrimp culture increased by one hundred thousand acres in the same area which raised concerns about the impact of saltwater intrusion into the surrounding agricultural lands. Stimulated by a spectacular rise in the demand for brackish water shrimp in the international market, its culture expanded horizontally and engulfed almost the entire coastal belt of the country. More importantly, shrimp culture reduced the availability of cropping land by raising soil salinity. The extent of salinity in groundwater is also increasing because of fresh agricultural land coming under shrimp culture. The area of saltwater-based shrimp culture has increased, as mentioned earlier, and if things continue in the same vein it will be difficult to find any cropping land in Khulna and Satkhira in the not-too-distant future. Coupled with successive cyclonic storms soil salinity has rendered people jobless and they are migrating elsewhere in search of employment.
Salinity intrusion is spreading across the non-coastal areas as well. A recent Seed Study of International Rice Research Institute (IRRI) has identified 12 districts of Bangladesh as salinity affected area through GIS mapping.
Biodiversity, environment and agriculture are being badly affected due to salinity in the south-western region. Local rivers which are mainly dependent on the Ganges are drying up due to uptake of water at the upstream. Influential people grabbed this opportunity to cultivate shrimps in saline water by destroying agricultural fields.
Due to all these factors people of this area are being thrown into increasing unemployment. Scarcity of drinking water in the area has reached its climax. Children and women are the worst sufferers and the number of poor is compounding. According to the UNDP, the World Food Programme (WFP) and the latest survey report of the Bangladesh Bureau of Statistics (BBS) published in August 2016, 50 per cent Khulna's population is ultra-poor while the number is 55 per cent in Satkhira and basically salinity created in the area as a result of the negative climatic impact is responsible for it.
As per information by the BBS, although population of the country is increasing, population in Khulna is declining. A research study says, population of Khulna went down by 60,000 between 2001 and 2011. Crops are not growing because of soil salinity in land. Sweet water supply has to be increased to contain salinity intrusion and flow of saline water from the sea has to be prevented. Additionally, shrimp culture by destroying farm lands has to be stopped. Drying rivers have to be dredged to restore navigability. Above all, in order to maintain ecological balance in the south-western region, agricultural lands in the coastal regions particularly of Khulna and Satkhira will have to be protected from salinity.
